Process of cleaning printing-surfaces.



-is, ten drops UNITED STATES FREDERICK FORSTER,

wept/ Patented July 18, 1905.

PATENT OFFICE.

OF NEW YORK, N. Y

. SPECIFICATION forming part of Letters Patent No. 795316, dated July 18, 1905.

Original application filed November 25, 1904, Serial No. 284,307. Divided and this application filed January 13 1905. Serial No. 240,878.

'1?) all w/mm It HULL/130711087721.

Be it known that I, FREDERICK FORS'JER, of New York, in the county of New York and State of New York, have invcn ted certain new and useful Improvements in Processes of Cleaning Printing-Surfaces; and I hereby de-' clarc that the followingis a full,clear, and exact description thereof.

This invention is an improved proeess'of cleaning printing-surfaces, particularly lithographic plates, such as aluminium, zinc, German or American printing metal, and other materials used for making printing-surfaces for plate-printing. The process may also be used in cleansing other surfaces and objects, and therefore 1 do not wish to be restricted specifically to its use for cleaning printingsurfaces.

The invention consists in the novel process of cleaning printing-surfaces, as hereinafter described and claime In my cleansing process 1 use two cleaning solutions which I shall designate as solution No. 1 and solution No. 2. These solutions are compounded as follows:

. Solution 1V0. 1.--Bichr0mate of potassium, one part; sulfuric acid; two parts; water, twenty parts.

Solution 1V0. 2.-Powdered purified alum, four parts; carbonate of soda, four parts; carbonate of potassium, one part; ten-per-cent. solution gallic acid, ten drops; caustic hydrate of soda, four parts; water, thirty-two parts.

In compounding solution N0. 2 I prefer to first mix the alum and water, care being taken to remove or keep out any foreign substances or chemicals. The othcringredients are then added thereto.

As the strength of the chemicals varies somewhat, the actinomcter hydrometcr test for solution No. 2 is eighty. The solution of gallic acid is to be used in the proportion stated when each part represents an ounce'that of gallic acid to each thirteen ounces of chemicals used, exclusive of water.

For cleaning aluminium, zinc, white-metal,

pouring same evenly thereover.

German printing metal, Anlel'wh-u rinting metal, and all other materials commonly used for lithographic printing purposes in the form of plates'I proceed as follows:

First, place the plate in an ordinary asphaltum-lined trough and apply solution No. 1 by Let the solution remain on plate for about five minutes, then rub plate with felt or other soft material for the purpose of removing surface dirt. Afterward flush plate with water andiinally dry plate.

Second, apply solution No. 2 to the aforesaidplate in the same manner as above, distributing it evenly over plateand rubbing it gently at intervals for six or seven minutes with felt or other soft material which will remove all ink, grease, and other foreign matter. Then flush the plate with water; Again apply solution No. 1 thereto for, "a minute or two, and afterward give plate a final washing with plain water and put in rack to dry.

The plate thus treated will be thoroughly cleansed and prepared for use for lithographic printing without any other preparation or solution being used and with ut any rubbing except as stated above.

Having thus described my invention, what I claim asncw, and desire to secure by Letters Patent, is-- f. The herein-described process of cleaning printing-surfaces and other objects, consisting in first applying to the surface a solution composed of bichromatc of potassium, sulfuric acid and water; then washing the surface; second applying to the surface a solution composed of alum, carbonate of soda, carbonate of potassium, gallic acid, caustic alkaliand water, rubbing the surface gently and finally washing and drying the surface.

2. The herein-described process of cleaning printingrsurfaces and other objects, consisting in first applying to the surface a solution composed of hichromate of potassium. sulfuric acid and water; then washing and drying the surface; second applying to the surface a solution of alum, carbonate of soda, my own I aliix my signature in presence of two carbonate of potassium, gallic' acid, caustic witnesses. alkali and water, rubbingitlthei'eon gently and I then washing the plate; then again applying 5 the last-named solution to the surface, and In presence of finally washing and drying the surface. FRANK (3. ll. \Vm'rn,

In testimony that 1 claim the foregoing as M. T. B n'nmx.

FR El) ER l( l\' FOR STER. 

